The present invention related to a method for producing an article comprising a substrate such as ceramics, plastics, metals or the like supporting thereon a silica-based film coated article, a silica-based film-coated article, a liquid composition for silica-based film coating, a method for producing an article comprising the silica-based film supporting thereon a functional film coated, and a functional film-coated article.
There are known various technologies in which a silica primer film or other oxide primer films are provided between a substrate and a functional film in forming a functional film on the surface of the substrate such as glass or other material, for the purpose of improving bonding strength between the substrate and the functional film, and preventing diffusion of an alkali component and improving durability of the functional film when the substrate contains an alkali component.
As methods for providing this oxide primer film, there are known sol-gel methods (Japanese Patent Publication No. 20781 of 1992, Japanese Laid-Open Patent No.311332 of 1990), methods in which a solution prepared by dissolving chlorosilane in a non-aqueous solvent is applied (Japanese Laid-Open Patent No. 86353 of 1993, Japanese Patent No. 2525536 (Japanese Laid-Open Patent No.238781 of 1993)), CVD methods, vapor deposition methods and the like.
In these methods, the main point thereof is the increase in the number of hydroxyl groups on the surface of the primer film for improving bonding strength with the functional film. However, there have been problems in that the hydroxyl group on the surface of the primer film tends to adsorb water contained in air, if water is once adsorbed, it is difficult to remove it with any ease, so heating is necessary at about 100 to 200xc2x0 C. in applying the functional film (the abovementioned Japanese Patent Publication No.20781 of 1992, Japanese Laid-Open Patent No. 311332 of 1990, Japanese Laid-Open Patent No. 238781 of 1993) or treatment for a long period of time is necessary even when heating is not necessary (the abovementioned Japanese Laid-Open Patent No. 86353 of 1993).
In the methods in which the oxide primer film is formed (the abovementioned Japanese Laid-Open Patent No. 311332 of 1990, Japanese Patent No. 2525536), strength of the primer film itself is low by only applications at normal temperatures, therefore, baking at a temperature of about 500 to 600xc2x0 C. after the application is indispensable when increasing strength. Furthermore, when the substrate contains an alkali, it is necessary to form an oxide primer film having a thickness of 100 nm or more for preventing diffusion of the alkali during the baking. However, there have been problems in that when the thickness of the primer film increases, the film thickness tends to become uneven, appearance failures such as reflection unevenness and the like tend to occur, production cost increases, and the like.
Furthermore, in the method in which a solution prepared by dissolving tetrachlorosilane into a non-aqueous solvent such as perfluorocarbon, methylene chloride and hydrocarbon is applied (the abovementioned Japanese Patent No. 2525536), scratch resistance is low though a silica primer film is obtained at normal temperatures. A chlorosilyl group has extremely high reactivity, and in the case of a coating solution, it is necessary to conduct the coating under an environment containing no storage water, whereby the production cost is consequently undesirable.
An object of the present invention is to solve the abovementioned problems of the prior art and to provide a method for producing in a short period of time and with ease a silica-based film-coated article excellent as a primer film and a functional film-coated article excellent in durability without requiring treatment leading to an increase in production costs such as baking and the like.
In the present invention, a silica-based film which is durable and has an alkoxyl group on the surface is coated on the surface of a substrate by applying on the substrate an alcohol solution composed of a silicon alkoxide in low concentration and a volatile acid in high concentration and drying at a normal temperature, and a functional film is allowed to be bonded to the substrate securely by applying on this silica-based film an organosilane having a hydrolyzable group and a functional group having a specific function, for solving the abovementioned problems.
Namely, the present invention is a method for producing a silica-based film-coated article by applying on a substrate a coating liquid composed of an alcohol solution containing a silicon alkoxide and an acid, wherein said coating liquid comprises;
(A) silicon alkoxides having at least two alkoxide groups or hydrolyzates thereof (including a partial hydrolyzate), 0.010 to 3% by weight (in terms of silica)
(B) an acid 0.0010 to 1.0 normality, and
(C) water 0 to 10% by weight.
The phrase xe2x80x9cin terms of silica,xe2x80x9d as used herein, is understood to mean that the Si content is calculated as SiO2 as if all the Si contained in silicon alkoxide were to be converted to SiO2.
The contents of the component (A) of 0.010 to 3% by weight (in terms of silica) is applicable when a silicon alkoxide and a hydrolyzate thereof are used alone, respectively, and also when they are mixed for use.
In the present invention, the silicon alkoxide used in the abovementioned coating liquid is not particularly restricted, and examples thereof include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane and the like, and preferably, silicon alkoxides having relatively low molecular weight, for example, tetraalkoxysilanes having an alkoxyl group with 3 or less carbon atoms is used since they tend to form a compact film. Furthermore, polymers of these tetraalkoxisilanes having an average polymerization degree of 5 or less are preferably used.
As the acid catalyst used in the abovementioned coating liquid, volatile acids such as hydrochloric acid, hydrofluoric acid, nitric acid, acetic acid, formic acid, trifluoroacetic acid and the like are preferable since they vaporize and do not remain in the film by drying at normal temperatures, and among them, hydrochloric acid which has high volatility and of which handling is relatively easy is particularly preferable.
Furthermore, the alcohol solvent used in the abovementioned coating liquid is not particularly restricted, and examples thereof include methanol, ethanol, 1-propanol, 2-propanol, butyl alcohol, amyl alcohol and the like. Among them, linear saturated monohydric alcohol having 3 or less carbon atoms such as methanol, ethanol, 1-propanol, 2-propanol and the like is preferably used since evaporation speed thereof at normal temperatures is high.
In the coating liquid composed of an alcohol solution containing a silicon alkoxide, an acid and water (including that used for dissolution of the acid, that is generated from impurities in the solvent and from the atmosphere, and the like), hydrolysis reaction represented by the following formula (1) between a silicon alkoxide and water is carried out, during preparation, during storage and after application of the liquid. In the formula, R represents an alkyl group.
(xe2x80x94Sixe2x80x94OR)+(H2O)xe2x86x92(xe2x80x94Sixe2x80x94OH)+(ROH)xe2x80x83xe2x80x83(1)
The hydrolyzed silanol groups (xe2x80x94Sixe2x80x94OH) mutually cause dehydration condensation reaction as shown in the following formula (2) to form a siloxane bond (xe2x80x94Sixe2x80x94Oxe2x80x94Sixe2x80x94).
(xe2x80x94Sixe2x80x94OH)+(xe2x80x94Sixe2x80x94OH)xe2x86x92(xe2x80x94Sixe2x80x94Oxe2x80x94Sixe2x80x94)+(H2O)xe2x80x83xe2x80x83(2)
Whether or not the coating liquid composed of an alcohol solution containing a silicon alkoxide, an acid and water, the alkoxy group in the silicon alkoxide causes hydrolysis reaction as shown in the abovementioned formula (1), or whether the hydrolyzed groups (xe2x80x94Sixe2x80x94OH) mutually cause dehydration condensation reaction as shown in the abovementioned formula (2) in the abovementioned coating liquid or more depends significantly on the acid concentration of the solution, the concentration of the silicon alkoxide or the hydrolyzate thereof, and water content. When the concentration and water content of the silicon alkoxide are lower, the abovementioned reaction (1) does not easily occur and, consequently, the abovementioned reaction (2) also does not easily occur. When the acid concentration of the solution is within the pH range from 0 to 3, the abovementioned reaction (1) proceeds quickly, however, the abovementioned reaction (2) does not occur easily.
In the present invention, the degree of polymerization of the silicon alkoxide in the coating liquid is kept as low as possible before application by repressing the abovementioned dehydration condensation reaction, and when this coating liquid is applied on the surface of the substrate and dried, the abovementioned reactions (1) and (2) are allowed to occur suddenly to form a siloxane bond, and it is thus possible to form a compact film at normal temperatures.
If a silicon alkoxide is subjected to hydrolysis reaction and polycondensation reaction in a solution as in prior art, polymers mutually bond when the solution is applied on the surface of a substrate and dried, therefore, voids tend to be formed and a compact film is not formed, and curing by baking for obtaining a compact film is required. In the present invention, the silicon alkoxide in the coating liquid and hydrolyzate thereof (including a partial hydrolyzate) are preferably a monomer or a polymer of 20-mer or less. However, when the total amount of a monomer or a polymer of 2-mer or less is 80% by weight or more based on the total amount of the silicon alkoxide and hydrolyzate thereof (including a partial hydrolyzate), a polymer of over 20-mer can be contained without causing problems.
In the present invention, by keeping the concentration of the acid catalyst in the coating liquid at 0.0010 to 1.0 normality, pH of the coating liquid becomes 0 to 3, and particularly when pH is about 2, the hydrolysis reaction of the remaining alkoxyl group in the reaction formula (1) and dehydration condensation reaction in the reaction formula (2) do not easily occur in the coating liquid before application, and these reactions progress steeply directly after the coating liquid is applied. The preferable concentration of the acid in the coating liquid is from 0.01 to 1.0 normality.
It is preferable that the acid to be added as a catalyst has a high concentration of 0.3-fold or more of water content, to keep the concentration of the acid in the coating liquid. Namely, when an acid in the form of an aqueous solution is used, an acid of high concentration having a concentration of 23.1% or more, for example, an aqueous hydrochloric acid solution of about 6.3 normality or more is preferable. Furthermore, when an acid in the form of a solution dissolved in ethanol is added as a catalyst, if this ethanol solution contains water, for example in an amount of 0.5% by weight or more, it is preferable that the concentration of the acid in the ethanol solution is 0.15% by weight or more (0.3-fold of 0.5% by weight), for example, is 0.04 normality or more in the case of hydrochloric acid.
It is preferable that the concentration of at least one of either the silicon alkoxide in the coating liquid or hydrolyzate thereof (including a partial hydrolyzate) is as low as possible, since the hydrolysis reaction of the remaining alkoxyl group in the reaction formula (1) and the dehydration condensation reaction in the reaction formula (2) do not easily occur in the coating liquid before the application, which is also dependent on pH of the coating liquid. However, when this concentration is too low, the thickness of the silica film becomes too low, for example, becomes less than 5 nm, and uniform coating of the substrate becomes difficult, and when the substrate contains an alkali component, the ability to prevent diffusion of the alkali component tends to decrease and lower durability, and when a functional film is coated thereon, strong bonding of the functional film on the silica film becomes impossible. Furthermore, when the concentration of at least one of either the silicon alkoxide or the hydrolyzate (including a partial hydrolyzate) is over 3% by weight, the thickness of the resulting silica film exceeds 300 nm, and the resulting film tends to be scratched and is not strong. Therefore, the range of the concentration of at least one of either the silicon alkoxide in the coating liquid or the hydrolyzate (including a partial hydrolyzate)(including a polymer of less than 20-mer) is from 0.010 to 3% by weight, preferably from 0.010 to 0.6% by weight in terms of silica.
When the concentration of at least one of either the silicon alkoxide or the hydrolyzate (including a partial hydrolyzate) is kept relatively high, it is preferable to keep the concentration of the acid catalyst in the coating liquid relatively high. Specifically, it is preferable that the coating liquid contains (A) at least one of either the silicon alkoxide or the hydrolyzate (including a partial hydrolyzate) and (B) the acid, in a proportion of [the component (B) (normality)/the component (A) (% by weight)] 0.010 or more, and it is preferable still at 0.03 or more.
When a large amount of water exists in the coating liquid, hydrolysis reaction of the silicon alkoxide is promoted in the liquid and dehydration condensation reaction tends to occur, and in drying after application of the coating liquid, unevenness of the film thickness tends to occur, therefore, it is preferable that the concentration of water in the coating liquid is as low as possible. Therefore, the concentration of water in the coating liquid is from 0 to 10% by weight, and preferably from 0 to 2% by weight.
By thus maintaining the concentration of water in the coating liquid, the hydrolysis reaction of the remaining alkoxyl group in the reaction formula (1) and the dehydration condensation reaction in the reaction formula (2) do not easily occur in the coating liquid before the application, which is also dependent on keeping the pH in the coating liquid and keeping the concentration of at least one of either the silicon alkoxide in the coating liquid or the hydrolyzate thereof (including a partial hydrolyzate). Even if the concentration of water in the coating liquid is zero, the hydrolysis reaction is not disturbed since the film after being coated on the substrate absorbs water in air. However, since a usual alcohol solvent originally contains a small amount of water and the acid is often added in the form of an aqueous solution, the concentration of water in the coating liquid is usually 0.1% by weight or more.
When the concentration of the acid catalyst in the coating liquid is kept relatively low, it is preferable that the water content of the coating liquid is kept relatively high, and, when the concentration of water in the coating liquid is kept relatively low, it is preferable that the concentration of the acid catalyst in the coating liquid is kept relatively high. Specifically, the coating liquid preferably contains the acid (B) and water (C) in an amount of [the component (B) (normality) X the component (C) (% by weight)] of 0.0020 or more. For example, when the concentration of the acid catalyst in the coating liquid is less than 0.003 normality and the concentration of water is zero or very low, the hydrolysis reaction tends to be insufficient by water absorption only from air into the applied film. Therefore, it is preferable that a coating liquid having a concentration of the acid catalyst of, for example, 0.0010 normality contains water in an amount of about 2.0% by weight or more.
When a silicon alkoxide and an acid are dissolved in the abovementioned proportion into an alcohol solvent and the resulting solution is stirred, mainly the silicon alkoxide forms a hydrolyzate by the reaction (1) and a part of the hydrolyzate causes dehydration condensation reaction by the reaction (2), in the solution. Thus, coating liquid is prepared, and in this coating liquid, the silicon alkoxide exists in the form of a monomer (including a hydrolyzate) or a polymer of less than 20-mer.
When the abovementioned coating liquid is applied on a substrate, the coated liquid that has formed a film has increased the specific surface area, consequently, the alcohol solvent in the film quickly vaporizes, and the concentration of at least one of either the silicon alkoxide or the hydrolyzate thereof (including a partial hydrolyzate) increases steeply, the hydrolysis reaction and the dehydration condensation reaction (including further polycondensation reaction of the abovementioned polymer of less than 20-mer) which have been suppressed suddenly occur to form a large amount of siloxane bonds (. . . Sixe2x80x94Oxe2x80x94Si. . . ) in the applied film, and as a result, a film mainly composed of silica having high compactness and having a thickness of 5 to 300 nm is formed causing a strong bond between the surface of the substrate and the film. Thus, in the present invention, reactivity in film-forming is high, a film extremely compact is formed by reaction at room temperature, and baking thereafter is not necessary.
As in the prior art, coating liquid before an application contains a large amount of siloxane bonds generated by a dehydration condensation reaction, and when a polymer having a polymerization degree of 20 or more is contained, the resulting silica film contains siloxane bonds, however, siloxane bonds connecting the surface of the substrate and the silica film are not formed in such large amounts, therefore, the bond between the surface of the substrate and the silica film is not so strong. For reinforcing this bond, conventionally baking at higher temperatures is further required.
Furthermore, according to the present invention, since hydrolysis reaction and dehydration condensation reaction of the silicon alkoxide partial hydrolyzate which has not been completely hydrolyzed in the abovementioned coating liquid progress simultaneously, an alkoxyl group is not hydrolyzed and remains on the surface of the formed silica film, and when a functional film is coated on this silica film as a primer film as described below, the adhesion of the functional film can be improved. For forming a compact silica film by a conventional sol-gel method, it is necessary that the dehydrated and concentrated silica film is usually heated at temperatures from 500 to 600xc2x0 C.
In the present invention, a compact silica film is formed only by natural drying or forcible drying at normal temperatures (e.g., at room temperature) or at a temperature of 150xc2x0 C. or less for 30 seconds to 5 minutes after application of the abovementioned coating liquid. When the abovementioned applied film is heated at a temperature of 150xc2x0 C. or more, the silica film neither increases the compactness further, nor improves adhesion of the functional film to be coated on the silica film.
Whether an alkoxyl group remains on the surface of the abovementioned silica film or not is known by measuring the static water drop contact angle on the surface of the silica film. As described in examples below, the static water drop contact angle of the surface of the silica film according to the present invention is from 20 to 40xc2x0. In contrast, when a silica film is formed by the conventional sol-gel method and baked at a temperature of 500 to 600xc2x0 C. for compactness of the film, the value of the static water drop contact angle is several degrees or less. The reason for such a decrease in the static water drop contact angle is hypothesized in that though alkoxyl groups remain on the surface of the silica film before baking, the alkoxyl groups are decomposed by the abovementioned baking and the number of hydroxyl groups on the surface of the silica increases for hydrophilization.
Even if a silica film having a hydroxyl group on the surface thereof is utilized as a primer film, and liquid for forming a functional film containing an organosilane is applied on the primer film, water in air bonds to a hydroxyl group on the surface of the silica primer film and water is adsorbed on the surface of the primer film before application of the organosilane, in a usual environment, therefore, it is difficult to form a chemical bond between the silica primer film and the organosilane at normal temperatures.
In the present invention, since the surface of the silica film has a large amount of alkoxyl groups remaining and a few hydroxyl groups, adsorption of water in air onto the surface of the primer film is believed to be prevented. Therefore, when liquid for forming a functional film containing an organosilane is applied on this silica primer film, a chemical bond can be formed between the silica primer film and the organosilane at normal temperatures and the functional film can be adhered securely to the silica primer film by a reaction between the alkoxyl group on the silica primer film and the silanol group on the organosilane (hydroxyl group or hydrolyzed functional group).
Also regarding surfaces of oxide-based primers, glass and ceramics, or hydrophilizated metal and plastics, it is difficult to form a chemical bond between applied organosilanes as described above, however, according to the present invention, a functional film can be securely adhered to a substrate by forming on the surface of this substrate a silica primer layer having an alkoxyl group remaining. When this silica primer film is heated at high temperatures, the remaining alkoxyl group disappears, and a hydroxyl group is formed instead, therefore, when the functional film to be coated thereon is to be adhered securely, the silica primer film should not be heated previously at a temperature of over 150xc2x0 C.
Furthermore, the silica film formed by the present invention has extremely excellent surface smoothness. Therefore, a functional film obtained by applying a functional organosilane on this silica film primer also has extremely excellent surface smoothness. Namely, the surfaces of the silica film and the functional film have an arithmetical mean roughness of (Ra)=0.5 nm or less, particularly of 0.10 to 0.5 nm, and have a ten points mean roughness of (Rz)=5.0 nm or less, particularly of 1.0 to 5.0 nm. This surface roughness Ra and Rz can be measured using an atomic force microscope (AFM)(manufactured by SEIKO Electronics Co., Ltd., scanning type probe microscope xe2x80x9cSPI3700xe2x80x9d, cantilever; made of silicon xe2x80x9cSI-DF20xe2x80x9d) by a method in which JIS B 0601 defined by two dimensions is enlarged to three dimensions. In this case, the measuring area of the sample was the square of 1 xcexcmxc3x971 xcexcm, and the surface form was measured at a measuring point number of 512xc3x97256, a scanning speed of 1.02 Hz and DFM (cyclic contact mode), correction by a low-pass filter and leveling correction of measured data (curve was drawn by approximate least-squares method and fitted, inclination of data was corrected, furthermore, strain in the z axis was deleted) were conducted and values of the surface roughness Ra and Rb were calculated.
One reason why a functional film coated on the silica-based film according to the present invention has excellent water-repellent performance, excellent low abrasion resistance, excellent water drop rolling property, excellent pollution resistance and excellent durability is assumed to be due to excellent smoothness of the surface of the functional film coated on a silica film having excellent smoothness. And the reason for this excellent smoothness obtained of the silica film is hypothesized as follows. Namely, it is estimated that a silicon alkoxide is uniformly dissolved in a solvent in the form of a monomer (including a hydrolyzate) or a polymer of 20-mer or less in coating liquid before application, and after application, a compact silica film is formed at room temperature by effects of the existence of an acid catalyst in high concentration and a steep increase in concentration of the silicon alkoxide (including a hydrolyzate), therefore, excellent smoothness is obtained.
In comparison, when a solution prepared by dissolving, for example, a chlorosilyl group-containing compound such as tetrachlorosilane into a non-aqueous solvent is applied instead of the silicon alkoxide used in the present invention, because of very high reactivity of the chlorosilyl group-containing compound, the reaction becomes ununiform, and the surface roughness of the resulting film is for example 7.9 nm in terms of arithmetic mean roughness of (Ra) or 29.8 nm in terms of ten points mean roughness (Rz) manifesting poorer smoothness as compared with that of the present invention.
The abovementioned illustrations relate to coated articles of a film composed of only silica, however, the present invention can be applied also to coated articles of a film mainly composed of silica. Namely, durability can be further improved by adding as a film component an oxide of an atom other than silicon such as aluminum, zirconium, titanium, cesium and the like and by substituting the silica in an amount of at most 30% by weight, usually from 1 to 30% by weight in terms of the oxide to give a silica-based multi-component oxide film. Among them, aluminum and zirconium are preferable since they reinforce the primer itself and reinforce the bond with a functional film. When the amount added by the oxide of an atom other than silicon is less than 1% by weight, the effects by addition are not obtained, and when over 30% by weight, the compactness of the film is lost and durable film is not obtained.
It is preferable that these oxides are added in the form of a chelated compound obtained by chemically modifying an alkoxide of these metals with xcex2-diketone, acetic acid, trifluoroacetic acid, ethanolamine and the like. In particular, when a metal alkoxide is chemically modified with acetylacetone which is one xcex2-diketone, stability of the solution is excellent and a relatively durable film is obtained.
For producing the silica-based film-coated article according to the present invention, coating liquid composed of the abovementioned alcohol solution is applied on the surface of a substrate such as glass, ceramics, plastics, metals and the like under normal temperatures and normal pressure, and naturally dried or forcibly dried under normal temperatures and normal pressure or at a temperature of 150xc2x0 C. or less for 30 seconds to 5 minutes.
Since a hydrophilic group such as a hydroxyl group exists on the surface of a substrate such as glass, ceramics and metal, when the abovementioned coating liquid is applied, a film is formed on the substrate. However, depending on the kind of plastic substrates, the number of hydrophilic groups on the surface thereof may sometimes be low and wetting property with alcohol is poor, then, the coating liquid may be repelled on the substrate surface and a film may not be easily formed. In the case of such a substrate having a few hydrophilic groups on the surface thereof, it is preferable that the surface is previously treated by plasma containing oxygen or a corona atmosphere for hydrophilization, or the substrate surface is irradiated with ultraviolet rays having wavelengths of about 200 to 300 nm in an atmosphere containing oxygen to conduct hydrophilization treatment, then, silica-based film coating treatment is conducted.
The method for applying the coating liquid for forming a silica-based film is not particularly restricted, and examples thereof include dip coat, flow coat, spin coat, bar coat, roll coat, spray coat, a hand applying method, a brush applying method and the like.
According to the present invention, a compact and hard silica-based film can be formed on the surface of a substrate such as glass, ceramics, metal, plastics and the like without heating at high temperature. This film has the ability to block an alkali from the substrate, or is useful as a primer film for improving bonding strength between the substrate and a functional film, and a functional film can be formed such as a water-repellent film, oil repellent film, mist resistant film, pollution resistant film, high abrasion resistant film, reflection resistant film or other optical film, electrically conductive film, semiconductive film, protective film and the like, by applying, for example, an organosilane having a hydrolyzable group and a functional group having a specific function or a hydrolyzate thereof (including a partial hydrolyzate) onto the abovementioned silica-based film or by conducting other coating.
The hydrolyzable group of the abovementioned organosilane is not particularly restricted, and examples thereof include halogen, hydrodien, alkoxyl, acyloxy, isocyanateand the like. In particular, the alkoxyl group is preferable since the reaction thereof is not extremely severe and handling thereof such as storage and the like is relatively easy.
The coating method for water-repellent and oil repellent functional film is not particularly restricted, and methods in which treatment is conducted using a fluoroalkyl group as a water-repellent functional group and an organosilane having a hydrolyzable group are preferable.
As the organosilane containing a fluoroalkyl group, perfluoroalkyl group-containing trichlorosilanes such as CF3(CF2)11(CH2)2SiCl3, CF3(CF2)10(CH2)Si(Cl)3, CF3(CF2)9(CH2)2SiCl3, CF3(CF2)8(CH2)2SiCl3, CF3(CF2)7(CH2)2SiCl3, CF3(CF2)6(CH2)2SiCl3, CF3 (CF2)5(CH2)2SiCl3, CF3(CF2)4(CH2)2SiCl3, CF3(CF2)3(CH2)2SiCl3, CF3(CF2)2(CH2)2SiCl3, CF3CF2(CH2)2SiCl3, CF3(CH2)2SiCl3; perfluoroalkyl group-containing trialkoxysilanes such as CF3(CH2)2SiCl3CF3(CF2)11(CH2)2Si(OCH3)3, CF3(CF2)10(CH2)2Si(OCH3)3, CF3(CF2)9(CH2)2Si(OCH3)3, CF3(CF2)8(CH2)2Si(OCH3)3, CF3(CF2)7(CH2)2Si(OCH3)3, CF3(CF2)6(CH2)2Si(OCH3)3, CF3(CF2)5(CH2)2Si(OCH3)3, CF3(CF2)4(CH2)2Si(OCH3)3, CF3(CF2)3(CH2)2Si(OCH3)3, CF3(CF2)2(CH2)2Si(OCH3)3, CF3CF2(CH2)2Si(OCH3)3, CF3(CH2)2Si(OCH3)3, CF3(CF2)11(CH2)2Si(OC2H5)3, CF3(CF2)10(CH2)2Si(OC2H5)3, CF3(CF2)9(CH2)2Si(OC2H5)3, CF3(CF2)8(CH2)2Si(OC2H5)3, CF3(CF2)7(CH2)2Si(OC2H5)3, CF3(CF2)6(CH2)2Si(OC2H5)3, CF3(CF2)5(CH2)2Si(OC2H5)3, CF3(CF2)4(CH2)2Si(OC2H5)3, CF3(CF2)3(CH2)2Si(OC2H5)3, CF3(CF2)2(CH2)2Si(OC2H5)3, CF3CF2(CH2)2Si(OC2H5)3, CF3(CH2)2Si(OC2H5)3; perfluoroalkyl group-containing triacyloxysilanes such as CF3(CF2)11(CH2)2Si(OCOCH3)3, CF3(CF2)10(CH2)2Si(OCOCH3)3, CF3(CF2)9(CH2)2Si(OCOCH3)3, CF3(CF2)8(CH2)2Si(OCOCH3)3, CF3(CF2)7(CH2)2Si(OCOCH3)3, CF3(CF2)6(CH2)2Si(OCOCH3)3, CF3(CF2)5(CH2)2Si(OCOCH3)3, CF3(CF2)4(CH2)2Si(OCOCH3)3, CF3(CF2)3(CH2)2Si(OCOCH3)3, CF3(CF2)2(CH2)2Si(OCOCH3)3, CF3CF2(CH2)2Si(OCOCH3)3, CF3(CH2)2Si(OCOCH3)3 perfluoroalkyl group-containing triisocyanatesilanes such as CF3(CF2)11(CH2)2Si(NCO)3, CF3(CF2)10(CH2)2Si(NCO)3, CF3(CF2)9(CH2)2Si(NCO)3, CF3(CF2)8(CH2)2Si(NCO)3, CF3(CF2)7(CH2)2Si(NCO)3, CF3(CF2)6(CH2)2si(NCO)3, CF3(CF2)5(CH2)2Si(NCO)3, CF3(CF2)4(CH2)2Si(NCO)3, CF3(CF2)3(CH2)2Si(NCO)3, CF3(CF2)2(CH2)2Si(NCO)3, CF3CF2(CH2)2Si(NCO)3, CF3(CH2)2Si(NCO)3 can be exemplified.
Furthermore, a functional film having water-repellent performance or high abrasion resistance can also be obtained by treatment using an organosilane containing an alkyl group. This organosilane is not particularly restricted, and organosilanes containing a straight-chain alkyl group having 1 to 30 carbon atoms and a hydrolyzable group can be preferably used.
As the organosilane containing an alkyl group, alkyl group-containing chlorosilanes such as CH3(CH2)30SiCl3, CH3(CH2)20SiCl3, CH3(CH2)18SiCl3, CH3(CH2)16SiCl3, CH3(CH2)14SiCl3, CH3(CH2)12SiCl3, CH3(CH2)10SiCl3, CH3(CH2)9SiCl3, CH3(CH2)8SiCl3, CH3(CH2)7SiCl3, CH3(CH2)6SiCl3, CH3(CH2)5SiCl3, CH3(CH2)4SiCl3, CH3(CH2)3SiCl3, CH3(CH2)2SiCl3, CH3CH2SiCl3, (CH3CH2)2SiCl2, (CH3CH2)3SiCl, CH3SiCl3, (CH3)2SiCl2, (CH3)3SiCl; alkyl group-containing alkoxysilanes such as CH3(CH2)30Si(OCH3)3, CH3(CH2)20Si(OCH3)3, CH3(CH2)18Si(OCH3)3, CH3(CH2)16Si(OCH3)3, CH3(CH2)14Si(OCH3)3, CH3(CH2)12Si(OCH3)3, CH3(CH2)10Si(OCH3)3, CH3(CH2)9Si(OCH3)3, CH3(CH2)8Si(OCH3)3, CH3(CH2)7Si(OCH3)3, CH3(CH2)6Si(OCH3)3, CH3(CH2)5Si(OCH3)3, CH3(CH2)4Si(OCH3)3, CH3(CH2)3Si(OCH3)3, CH3(CH2)2Si(OCH3)3, CH3CH2Si(OCH3)3, (CH3CH2)2Si(OCH3)2, (CH3CH2)3SiOCH3, CH3Si(OCH3)3, (CH3)2Si(OCH3)2, (CH3)3SiOCH3, CH3(CH2)30Si(OC2H5)3, CH3(CH2 )20Si(OC2H5)3, CH3(CH2)18Si(OC2H5)3, CH3(CH2)16Si(OC2H5)3, CH3(CH2)14Si(OC2H5)3, CH3(CH2)12Si(OC2H5)3, CH3(CH2)10Si(OC2H5)3, CH3(CH2)9Si(OC2H5)3, CH3(CH2)8Si(OC2H5)3, CH3(CH2)7Si(OC2H5)3, CH3(CH2)6Si(OC2H5)3, CH3(CH2)5Si(OC2H5)3, CH3(CH2)4Si(OC2H5)3, CH3(CH2)3Si(OC2H5)3, CH3(CH2)2Si(OC2H5)3, CH3CH3CHQSi(OC2H5)3, (CH3CH2)2Si(OC2H5)2, (CH3CH2)3SiOC2H5, CH3Si(OC2H5)3, (CH3)2Si(OC2H5)2, (CH3)3SiOC2H5; alkyl group-containing acyloxysilanes such as CH3(CH2)30Si(OCOCH3)3, CH3(CH2)20Si(OCOCH3)3, CH3(CH2)18Si(OCOCH3)3, CH3(CH2)16Si(OCOCH3)3, CH3(CH2)14Si(OCOCH3)3, CH3(CH2)12Si(OCOCH3)3, CH3(CH2)10Si(OCOCH3)3, CH3(CH2)9Si(OCOCH3)3, CH3(CH2)8(OCOCH3)3, CH3(CH2)7Si(OCOCH3)3, CH3(CH2)6Si(OCOCH3)3, CH3(CH2)5Si(OCOCH3)3, CH3(CH2)4Si(OCOCH3)3, CH3(CH2)3Si(OCOCH3)3, CH3(CH2)2Si(OCOCH3)3, CH3CH2Si(OCOCH3)3, (CH 3CH2)2Si(OCOCH3)2, (CH3CH2)3SiOCOCH3, CH3Si(OCOCH3)3, (CH3)2Si(OCOCH3)2,(CH3)3SiOCOCH3; alkyl group-containing isoycanatesilanes such as CH3(CH2)30Si(NCO)3, CH3(CH2)20Si(NCO)3, CH3(CH2)18Si(NCO)3, CH3(CH2)16Si(NCO)3, CH3(CH2)14Si(NCO)3, CH3(CH2)12Si(NCO)3, CH3(CH2)10Si(NCO)3, CH3(CH2)9Si(NCO)3, CH3(CH2)8Si(NCO)3, CH3(CH2)7Si(NCO)3, CH3(CH2)6Si(NCO)3, CH3(CH2)5Si(NCO)3, CH3(CH2)4Si(NCO)3, CH3(CH2)3Si(NCO)3, CH3(CH2)2Si(NCO)3, CH3CH2Si(NCO)3, (CH3CH2)2Si(NCO)2, (CH3CH2)3SiNCO, CH3Si(NCO)3, (CH3)2Si(NCO)2, (CH3)3SiNCO can be exemplified.
Furthermore, a functional film can be obtained which manifests low critical inclined angles at which a water drop starts to roll and low pollution adsorption or adhesion by conducting treatment using an organosilane having a polyalkylene oxide group and a hydrolyzable group in the molecule.
As the abovementioned polyalkylene oxide group, a polyethylene oxide group, polypropylene oxide group and the like are mainly used. Examples of the organosilane having these groups include organosilanes such as [alkoxy(polyalkyleneoxy)alkyl]trialkoxysilane, N-(triethoxysilylpropyl)-O-polyethylene-oxide urethane, [alkoxy(polyalkyleneoxy)alkyl]trichlorosilane, N-(trichlorosilylpropyl)-O-polyethylene-oxide urethane and the like, and more specifically, [methoxy(polyethyleneoxy)propyl]trimethoxysilane, [methoxy(polyethyleneoxy)propyl]triethoxysilane, [butoxy(polypropyleneoxy)propyl]trimethoxysilane and the like are preferably used.
When this organosilane is dissolved in an alcohol solvent and hydrolyzed using an acid catalyst and the resulting solution is applied on the abovementioned silica-based film (primer film), a de-alcohol reaction occurs between an alkoxyl group on the surface of the primer film and a silanol group of the organosilane and the primer film is bonded to the organosilane via siloxane bond without conducting heat treatment. When the hydrolyzable functional group of the abovementioned organosilane has high reactivity, for example, when the organosilane has a chloro group, isocyanate group, acyloxy group and the like, the bond between the primer film and the organosilane is formed by a reaction of the group with silanol co-existing with an alkoxyl group on the surface of the primer film or a small amount of water, therefore, the abovementioned organosilane may be applied as it is without dilution or a solution prepared only by diluting the organosilane with a non-aqueous solvent such as perfluorocarbon, methylene chloride, hydrocarbon, silicone and the like may also be applied. As described above, a functional film can be securely adhered to a substrate by using as a primer film a silica-based film having an alkoxyl group remaining on the surface.
The method for applying a functional film is not particularly restricted like in the case of the coating treatment of a silica-based film, and examples thereof include flow coat, roll coat, spray coat, a hand applying method, a brush applying method and the like.